HDMI No Signal PC

Step-by-step checks before you replace parts

Plug into the GPU, not the motherboard HDMI

On most desktops with a discrete graphics card, the motherboard rear HDMI stays dark unless the integrated GPU is enabled and in use. Plugging into the wrong port is a top cause of HDMI no signal after a new build or GPU install.

First step: Look at the rear of the case. Ports on the removable metal bracket of the graphics card (usually lower/center) are the GPU outputs. Ports on the I/O shield aligned with the motherboard edge are motherboard outputs.

Steps

  1. Move the cable to a GPU HDMI or DisplayPort

    Unplug from the motherboard HDMI. Plug into the graphics card. Power on and recheck the monitor input.

    Rear of PC highlighting GPU bracket HDMI with red box and motherboard HDMI marked with red X
    Use the GPU bracket ports when a discrete card is installed.

  2. If you must use motherboard video

    You typically need the CPU to include graphics, the GPU removed or disabled per motherboard docs, and multi-monitor / iGPU settings configured in firmware. For a standard gaming GPU setup, prefer the card’s ports.

  3. After moving the cable, set projection mode

    Press Win+P and try Duplicate or Extend. Continue on input & Win+P if needed.

  4. Still dark after using the GPU port?

    Return to cable checks, then power on but no display / BIOS no signal.

What to do next

Image appears on GPU HDMI Wrong-port issue confirmed.
Both motherboard and GPU ports dark Check the cable and port, then power on but no display. Open BIOS / POST only when no firmware logo appears on any cable.

FAQ

Why did motherboard HDMI work before I installed a GPU?

With only integrated graphics, motherboard outputs are active. After installing a discrete GPU, many boards stop outputting on the I/O HDMI by default.

I only have DisplayPort on the GPU

Use DisplayPort or a proper DP/HDMI cable rated for your resolution. See DisplayPort no signal.

Official sources

Independent DIY troubleshooting. Prefer Microsoft and OEM support articles for model-specific steps. We do not sell one-click fix tools or host driver packs.